Grandpa's Words (Coke On The Rocks)

*cracks fingers* Let's get to this.

Don't let a qualm prowl to whisper near your mind,

Poetry is all about smooth, fluid movement to me (unless a poem is trying to convey a sense of brokenness or discontinuity) so any line that causes me to pause in the reading should be worked on. Imagine your poem as a bunch of pipes; this one is blocked up.
I thought at first that 'qualm' was an adjective to 'prowl', but after reading a few times I realized that it was a noun and that 'prowl' was the verb.
Long story short, I'm confused as to who is doing what in this sentence. I think removing the 'to' and 'prowl' would fix it: "Don't let a qualm whisper near your mind." But 'prowl' is a powerful word, giving a very distinct image. You might want to graft it in somehow.

it'll block your vision with its daunting lies.

I'm a bit of an old-fashioned person, so lines that aren't capitalized in a poem make me cringe a little. However, I have come to understand that this is a style and that my opinion on it rarely matters. It happens a bunch here, but I won't mentioned it again.
The real point on this line is that the 'its's' breaks the flow for me. Maybe if you changed it to: "Blocking your vision with its daunting lies."

Desqualify fear from being your ally;

Disqualify.

that is similar to slaying your own life.

Colorful, I like that you're straying from the conventional 'taking your own life'.

there's no time to be a pillar of salt.

I understand this Biblical reference, but if you want to delve deeply into it, it's not all about fear. The resounding theme of the story of Lot's wife is about not being able to let go of material possessions (I believe). Which, if you go deeper, is just another kind of fear, so whatever.

Make your eyes become your vigilant knights,

This line is gold. Only one change is all I see fit: "Make your eyes become vigilant knights,". I know it's not the same, but 'your' just feels redundant in that line. Maybe you should read both lines aloud for a while to decide. I'm not even decided on that.

but don't let uncertainty pluck out your spine.

Hmm, the word 'but' implies negating the previous idea, which this line is not doing. Either remove 'but' or replace it with another, more suitable conjunction.

Living is the most dangerous thing about life;

Love this line, keep doing it!

When your friends pout, become a truant.

I'm not sure what this line means. I feel like you chose the word 'truant' for its own merit, rather than for how it fit the other words.

And if you feel like that won't work,
get drunk on coke on the rocks."

This line caught me off guard in a nice way. I'd forgotten the quotation mark at the beginning.

A day before his pulse stopped,
these were my grandpa's words.

I don't know how you feel about it, but what if you switch these two lines around?

These were my grandpa's words
a day before his pulse stopped.

I think it gives it a little more finality.

Overall, the poem was great, but I still didn't understand that. Personally, I believe a perfect poem is one the reader immediately comes away with an idea, or is at least thinking hard. Of course, I couldn't write a half-good poem to save a hamster, so I'm nowhere near criticizing you of not having a perfect poem.
8/10: Would read again.
Jenth